Differential gear

ABSTRACT

Proposed is a locking differential drive, in which, between a first side of a differential cage ( 3 ) and a cover ( 4 ) a crown wheel ( 2 ) is located, which is turnably connected with the cover ( 4 ) and the differential cage ( 3 ), and the radial extent of which crown wheel ( 2 ) is less than that of the opening ( 9 ) of the differential cage ( 3 ), which said opening serves for the installation of differential bevel gears ( 10, 11 ). The crown wheel ( 2 ) exhibits two contact faces, of which a first contact face ( 7 ) serves as a seat for a clutch ( 6 ) of an externally lockable differential drive and a second contact face ( 8 ) serves as a seat for a clutch ( 17 ) of a self-actuating lockable differential drive. In this way, the same crown wheel ( 2 ) and the same differential cage ( 3 ) can be employed both for an externally lockable differential drive as well as a self actuating differential drive.

FIELD OF THE INVENTION

Differential gear drives are used frequently in motor vehicles, in orderto compensate for different rates of rotation of driven wheels. In thecase of lockable differentials, two kinds are generally differentiatedbetween. One is a lockable differential, which is put into the lockedstate by an external activation apparatus, in which, by the activationof the said external activation apparatus, the differential action ofthe differential can be partially or fully withheld. The other is theself-acting, locking differential. In the case of the self actingdifferential, the locking action is based on interior friction, whichopposes the differential motion. Usually, for both kinds of thedifferential, lamellar clutches are employed for the suspension of thedifferential activity.

BACKGROUND OF THE INVENTION

DE 195 47 980 A1 discloses a differential gear drive, which develops, bymeans of the varied speed of rotation of the driven wheels, a brakingtorque. This said torque partially suspends the differential action ofthe differential drive. In this case, the differential cage comprisestwo parts, which are connected by means of bolts. A bevel gear, which isdriven by a drive pinion, is connected to the differential cage by anadditional bolt fastening.

DE 38 39 787 C2 makes known a differential drive, in which case thedifferential effect of the said drive can be suspended by means of anexternal activation of an activation apparatus. The differential cage ofthe differential drive consists of two parts, wherein one part of thedifferential cage is driven. The fastening of the drive gear is notshown.

The purpose of the present invention is to create a differential drive,wherein the drive pinion and the driven bevel gear, which is connectedto the differential cage, as well as a principal component of thedifferential cage and the therein employed differential bevel gears, canserve as,an external lockable differential drive as well as aself-acting lockable differential drive.

SUMMARY OF THE INVENTION

In accordance with the invention, the driven bevel gear, which isconnected with the differential cage, is so designed, that it possessestwo, oppositely disposed contact faces. Of these two, the first contactface serves as seat for the clutch lamina which serve for the locking ofthe differential motion by externally activated locking means. Thesecond contact face, which lies opposite the first contact face, servesas a seat for a clutch in a self-locking differential drive. Thedifferential cage possesses on the one hand, an opening, through whichthe installation of the differential gears is made and which alsopossesses a space in which the clutches, in the case of a self-lockingdifferential drive can be installed and on the other hand, possesses afirst contact face for the bearing of the differential cage in the axlehousing. The drive side differential bevel gears, which are to be foundin the differential cage, possess fastening points for the securing ofthe inner laminae of the clutches for locking the differential drive.The driven bevel gear is so fastened as to turn in common with thedifferential cage and partially closes the opening of the differentialcage, whereby, the second contact face, which serves as a seat for theclutch of the self-locking differential drive, can extend itself intothe said differential cage. The driven bevel gear, which, as said, isrotatably affixed to the differential cage, is located between thedifferential cage and a cover, which cover is affixed by fasteningelements with both the driven bevel gear and the differential cage, andpossesses moreover a second location for the setting of the differentialdrive in bearings in the axle housing. While the driven bevel gear isplaced between the cover and the differential cage, it becomes possible,in accord with the individual circumstances, to permit the clutches toseat upon the said contact faces of the bevel gear. Different covers areused, if the lockable differential drive is to function as aself-locking drive or be activated by an external activation apparatus.By means of this arrangement, it is possible, in the case of aself-locking differential drive and also in the case of an externallyactivated locking differential drive, to make the principal componentsof the differential cage, the differential bevel gears in thedifferential cage, and the driven bevel gear, without any changes. If asplit axle housing is employed, which, can, possibly, encapsulate thedifferential drive, then, additionally, this part, which extends overthe differential drive, can also, for both kinds of differential drives,be made and shaped the same. By this means, it is possible to create anassembly method, in which both kinds of differential drives, with manyidentical components can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying drawings in which:

FIG. 1 a locking differential drive, which can be locked by externalactivation of an activation apparatus, and

FIG. 2 a locking differential drive, which, reduces the differentialeffect in a self-acting manner by means of variation in the speed ofrotation of the driven wheels.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1:

A drive pinion 1 drives a crown wheel 2, which is affixed to rotate withthe differential cage 3. The crown wheel 32 is placed between adifferential cage 3 and a cover 4. By means of an external, pressureconnected, activation means 5, upon application of pressure thereon, anaxial force is exerted on the clutch 6, which said clutch seats itselfagainst a first contact face 7 of the crown wheel 2. The crown wheel 2possesses a second contact face 8, with which the crown wheel 2 liesagainst the differential cage 3. The differential cage 3 possesses, oneopening 9, through which the differential bevel gears 10 may beinserted.

The output side differential bevel gears 11 possess, respectively, astructural member 12, which serves for the reception of the lamina ofthe clutch 6. The differential cage 3 is, first, carried in bearings bya bearing set 13 and, second, by a bearing set 14, both being located inthe axle housing 15. The cover 4, the crown wheel 2, and thedifferential cage 3 are so fastened by securing means as to turn witheach other.

FIG. 2:

A drive pinion 1 drives a crown wheel 2, which is connected to adifferential cage 3. The crown wheel 2 possesses two contact faces, afirst contact face 7 and a second contact face 8, whereby the secondcontact face 8 serves as a seat for the clutch 17 and also as a seat forthe crown wheel 2 on the differential cage 3. The differential gears 11,which can be mounted with the differential bevel gears 10 through anopening 9 in the differential cage 3, possess a structural element 12,on which the clutch 17 is placed. The differential cage 3 possesses,first, a bearing 13, and is, second, turnably secured by a fasteningmeans 16 to a cover 4 and the crown wheel 2, whereby the cover 4possesses a bearing set 14. By means of the bearing sets 13 and 14, thedifferential drive is carried on bearings in the axle housing 15.Inasmuch as the crown wheel 2, in its radial extent, is less than theradial extent of the opening 9 of the differential cage 3, it ispossible to make use of the crown wheel 2 as a contact face for theclutch 17. By means of the difference of the differential bevel gears11, a friction in the clutches 17 is produced, which minimizes thedifferential effect of the differential drive.

Reference Numbers and Items

1 Drive pinion

2 Crown wheel, also known as ring gear

3 Differential cage,

4 Cover

5 Activation apparatus

6 Clutch

7 First contact face

8 Second contact face

9 Opening in differential cage

10 Differential bevel gear

11 Differential bevel gear

12 Structural element

13 Bearing

14 Bearing

15 Axle housing

16 Fastening means

17 Clutch

What is claimed is:
 1. A differential drive, comprising rotatabledifferential housing including a differential cage (3), and a cover (4),a crown wheel (2) is secured on the cover, and a drive pinion (1) whichdrives the crown wheel (2), and at least one clutch (6, 17) foractuating one of a partial and a complete locking of a differentialeffect of the differential drive, the crown wheel (2) is located betweenthe cover (4) and the differential cage (3) and is fast with thedifferential cage (3) and the cover (4), and the crown wheel (2) has afirst and a second contact face (7, 8), the first contact face (7) ofthe crown wheel (2) serves as a seat for parts of the clutch (6), whichcan be activated to lock the differential effects of the differentialdrive by a locking apparatus, and the second contact face (8) of thecrown wheel (2) serves as a seat on the differential cage (3).
 2. Thedifferential drive according to claim 1, wherein the differential cage(3) has on a first side an opening (9), through which differential gears(10, 11) can be installed and on a second side has a bearing arrangement(13).
 3. The differential drive according to claim 2, wherein theopening (9) of the differential cage (3), through which the differentialgears (10, 11) can be installed, is located proximal to the crown wheel(2).
 4. The differential drive according to claim 1, wherein an innerradial extent of the contact faces (7, 8) of the crown wheel (2) is lessthan a radial extent of an opening (9) in a first side of thedifferential cage (3).
 5. The differential drive according to claim 1,wherein the cover (4) with a first bearing (14) and the differentialcage (3) with a second bearing (13) are secured in an axle housing (15).6. A differential drive, comprising a rotatable differential housingincluding a differential cage (3), and a cover (4), a crown wheel (2) issecured on the cover (4) and a drive pinion (1) drives the crown wheel(2), and at least one clutch (6, 17) for actuating one of a partial anda complete locking of a differential effect of the differential drive,wherein the crown wheel (2) is located between the cover (4) and thedifferential cage (3) and is fast with the differential cage (3) and thecover (4), the crown wheel (2) has a first and a second contact face (7,8), and the second contact face (8) of the crown wheel (2) serves as aseat for part of the clutch (17) which serves to produce a partialself-locking differential action of the differential drive, and thefirst contact face (7) of the crown wheel (2) serves as a seat for thecover (4).
 7. A differential drive comprising: a rotatable differentialhousing including a differential cage (3) and a cover (4); a crown wheel(2) is secured to the cover (4) and a drive pinion (1) drives the crownwheel (2); at least one clutch (6, 17) for one of partial and completelocking of a differential effect of the differential drive; wherein thecrown wheel (2) is located between the cover (4) and the differentialcage (3) and is fast with the cover (4) and the differential cage (3);the crown wheel (2) has first and second contact faces (7, 8); the firstcontact face (7) of the crown wheel (2) serves as a seat for a portionof the clutch (6) which can be activated, by a locking apparatus, tolock the differential effect of the differential drive, the secondcontact face (8) of the crown wheel (2) serves as a seat for thedifferential cage (3), and an inner radial extent of the first andsecond contact faces (7, 8) of the crown wheel (2) is less than a radialextent of an opening (9) in a first side of the differential cage (3).8. A differential drive comprising: a rotatable differential housingincluding a differential cage (3) and a cover (4); a crown wheel (2) issecured to the cover (4) and a drive pinion (1) drives the crown wheel(2); at least one clutch (6, 17) for one of partial and complete lockingof a differential effect of the differential drive; wherein the crownwheel (2) is located between the cover (4) and the differential cage (3)and is fast with the cover (4) and the differential cage (3); the crownwheel (2) has first and second contact faces (7, 8); the second contactface (8) of the crown wheel (2) serves as a seat for part of the clutch(17) which serves to produce a partial self-locking action of thedifferential drive; and the first contact face (7) of the crown wheel(2) serves as a seat for the cover (4), and an inner radial extent ofthe first and second contact faces (7, 8) of the crown wheel (2) is lessthan a radial extent of an opening (9) in a first side of thedifferential cage (3).
 9. A differential drive comprising: a rotatabledifferential housing including a differential cage (3) and a cover (4);a crown wheel (2) located between the cover (4) and the differentialcage (3) and non-rotatably attached thereto; and a drive pinion (1)driving the crown wheel (2); wherein the crown wheel (2) has first andsecond contact faces (7, 8), and the differential cage (3), the cover(4) and the crown wheel (2) are configured such that one of the firstand second contact faces (7 or 8) of the crown, wheel (2) is a seat fora clutch (6 or 17) and the other of the first and second contact faces(8 or 7) of the crown wheel (2) is a seat for one of the differentialcage (3) and the cover (4), whereby, upon operation of the clutch, theclutch is at least partially lock to provide a differential effect forthe differential drive.
 10. The differential drive according to claim 9,wherein the first contact face (7) of the crown wheel (2) is a seat forthe clutch (6) and the second contact face (8) of the crown wheel (2) isa seat for the differential cage (3), and the clutch is actuated tocompletely lock the clutch (6) and provide the differential effect ofthe differential drive.
 11. The differential drive according to claim 9,wherein the first contact face (7) of the crown wheel (2) is a seat forthe cover (4) and the second contact face (8) of the crown wheel (2) isa seat for the clutch (17), and the clutch is actuated to only partiallylock the clutch (17) and provide the differential effect of thedifferential drive.
 12. The differential drive according to claim 11,wherein the differential drive includes a second clutch (17) which islocated between the differential cage (3) a pair of differential gears(10, 11).